Transit center will be buzzing as hundreds of buses serve it, starting Sunday

An AC Transit bus does a dry run through the new bus level at the Transbay Transit Center.

Photo: Carlos Avila Gonzalez / The Chronicle

Beginning Sunday, commuter buses will rumble over the ramps that stretch from the Bay Bridge to the Transbay Transit Center, cutting an easy path into San Francisco’s South of Market district.

The East Bay agency AC Transit will operate the bus deck, renting bays to four other agencies. Together, they will run hundreds of buses in and out of the center every day, most of them making multiple trips.

They include 27 AC Transit lines to serve riders from Alameda and Contra Costa counties, with 140 buses operating during peak hours. On weekdays, Muni will run 617 buses to and from the ground-floor plaza and 69 buses via the bus deck. The San Francisco transit agency will trim down on weekends, with 390 buses driving through the plaza and 50 entering and departing from the deck.

Western Contra Costa Transit Authority will maintain a leaner service, with eight buses doing 24 trips in each direction on weekdays. But the agency plans to boost its fleet later this fall, adding three double-decker buses with a seating capacity of 87 — far more than the 56 on its regular buses.

Transbay Transit Center

Buses from Golden Gate Transit will make more than 120 trips each day, shuttling passengers between the North Bay and the transit center.

Greyhound will run 21 buses to and from the center every weekday and 22 on Saturdays and Sundays, traveling to Oakland, San Jose, Sacramento, Reno, Fresno and Los Angeles.

At this point, Amtrak will not run buses from its train stations in the East Bay, San Jose and Sacramento to the transit center. A spokesman for AC Transit said the two agencies are in negotiations.

Mohammed Nuru, president of the Transbay Joint Powers Authority — the agency that oversees the center — and San Francisco’s director of public works, didn’t seem concerned about the uncertainty. But he acknowledged, “Things are still being negotiated. … It’s like any new facility - everybody has what they want in terms of fees and details.”

That said, “we want this to be a one-stop facility,” Nuru said. “It’s a new type of bus station, very nice, more like an airport terminal.”

Service will be sparse on opening day, with AC Transit running its three traditional Sunday lines across the bridge. Normal service will start on Monday.

Rachel Swan covers transportation for The Chronicle. She joined the paper in 2015 and has also reported on politics in Oakland and San Francisco.

Previously, Rachel held staff positions at the SF Weekly and the East Bay Express, where she covered technology, law and the arts. She holds a Bachelor’s degree in rhetoric from the University of California, Berkeley.